(CBS News) Prosecutors are likely to use the obstruction of justice charges against Dzhokhar Tsarnaev's college friends as leverage to obtain further information about the Boston bombing suspect, CBS News legal analyst Jack Ford said on "CBS This Morning."

Azamat Tazhayakov, Dias Kadyrbayev and Robel Phillipos were arrested and accused Wednesday of removing a backpack containing fireworks emptied of gunpowder from Tsarnaev's dorm room three days after the attack to try to keep him from getting into trouble.

Tazhayakov and Kadyrbayev were charged with conspiring to obstruct justice by concealing and destroying evidence. Phillipos, was charged with lying to investigators about the visit to Tsarnaev's room.

"If I'm the prosecutor, I'm saying to (Tsarnaev's friends' lawyers) 'You guys want to help yourselves here? Here's what you got to do: start thinking back, what did you see, what did you hear? Was there some conversation? Maybe it didn't strike you as important back then, might be helpful for you right now.' Cooperation is always the first thing the judge will look at in sentencing, if they get to that stage," Ford said on "CBS This Morning."

Ford added the charges against them are serious. "You're talking about after-the-fact. ... There are no allegations that they knew anything about the bombing beforehand or contributed to the bombing, but law enforcement takes the notion of obstructing justice and interfering with investigations very seriously. They are often referred to as 'message cases' where prosecutors say, 'We want to get the message out there. You've got to cooperate with us. You can't lie to us and you can't be ditching evidence on here,' so if I'm their lawyers, I'm saying to them, 'Right now, guys, this is pretty serious stuff you're looking at.'"

The defense, Ford said, has to show they didn't really know what was in the backpack. "Obstruction of justice is you intentionally interfere with an investigation, legitimate investigation. Now, if they said, 'Hey, our buddy called us and said I've got a bag in my room and I don't want my girlfriend to see what's in there could you take that,' that's one thing."

Watch Jack Ford's full "CTM" interview above.

However, "CTM" co-host Norah O'Donnell noted, text messages may prove problematic to the college friends' defense.

Court documents say Kadyrbayev texted his friend Dzhokhar Tsarnaev saying he looked like one of the suspects in the bombings. Tsarnaev replied, "lol" -- shorthand for laugh out loud -- "you better not text me" and "come to my room and take whatever you want."

Police say the men then headed to Tsarnaev's dorm room at the University of Massachusetts Dartmouth. They watched movies before discovering a backpack with fireworks that had been emptied of their powder and a jar of Vaseline. That's when, according to the complaint, Kadyrbayev knew Tsarnaev was involved in the attack. And he decided "to remove the backpack from the room in order to help his friend Tsarnaev avoid trouble." He also grabbed Dzhokhar's laptop.

Ford said on "CTM," "The prosecution is going to say, 'Even if you don't know exactly what's in the bag, you're telling us if the prosecution can prove you got rid of it because you thought it might be harmful to your buddy in a serious investigation here,' then that's probably enough for obstruction of justice."

Kadyrbayev's attorney Robert Stahl has said his client "did not know that those items were involved in a bombing or any interest in a bombing or any evidential value."

The three friends "started to freak out," according to the complaint, once they saw that Dzhokar was a prime suspect. After hearing he and his brother Tamerlan fought police in a violent shootout -- Kadyrbayev "decided to throw away the backpack with the fireworks inside and Tazhayakov agreed."

Investigators found the bag last week in a New Bedford landfill,CBS News' Elaine Quijano reported. Sources tell CBS News the laptop has also been recovered.

So far, there's no evidence the three had knowledge of the Boston plot in advance. However, one of them did say that about a month before the attack Dzhokhar Tsarnaev casually mentioned he knew how to make a bomb, Quijano reported.

None of the men entered a plea in court Wednesday. If convicted, Kadyrbayev and Tazhayakov could face up to five years in prison. Phillipos could face up to eight years.